On the same day that our main army fought at Ostrolenka, the 26th of May, this little corps had an engagement with the enemy in the environs of Narewka. A considerable Russian detachment, under the command of general Rengardt, composed of 6,000 infantry, 3,000 cavalry, and five pieces of cannon--in all, nearly 9,000 men--was posted near Nasielsk. This considerable force was attacked by our small corps, to which were added some hundreds of insurgents, making in all, a force of not more than a thousand men. The Russians were completely beaten in this action. Full a thousand prisoners were taken, and all their artillery. An important advantage of this affair, was the taking of a great transport of some hundred vehicles with provisions, destined for the Russian grand army. By the dispersion and ruin of this corps, the department of Bialystok was entirely cleared of the Russians, and nothing interrupted the formation and organization of the insurgent forces. The taking of Bielsk, and the affair of Narewka, will be admitted by the reader to have been above the rank of ordinary achievements, and should immortalize the handful of brave men which formed this detachment. They may be pointed at, as examples, with many others, in this war, of how much can be effected by that prompt and energetic action which no ordinary motives will sustain. While the affairs of Lithuania and Samogitia, and those in the department of Bialystok, wore this favorable aspect, a new corps was approaching to aid this propitious state of things, to protect the insurrections, and, as might be confidently hoped, to bring them to a sure and happy result. The new force destined for this object consisted of the 2d division, reinforced by a squadron of cavalry, which force quitted Lomza on the 27th for Lithuania. Before returning to the operations of the grand army, we will give a short recapitulation of the forces which had been sent into Lithuania and Samogitia, at successive periods, to support the insurrections in those provinces. The first corps under general Chlapowski, left, on the 20th of May, the village of Xienzopol, with this destination;--to enter the department of Bialystok, to occupy the forest of Bialowiez, in which were collected the forces of the revolted Lithuanians, with the view to organize these forces; from that position to act on the Russian communications, and, if circumstances might allow it, to make an approach upon Wilno. This little corps, as we have seen, was composed of 190 infantry volunteers mounted, the 1st regiment of lancers, consisting of 480 horsemen, and two pieces of light artillery.